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  <script>

    // let a 
    // console.log(a)

    // function fn(x, y) {
    //   console.log(x+y)
    // }
    // fn()

    // let a = 10
    // let b = 20
    // a = 20
    // b = 30
    // console.log(a, b)

    function fn(a = 1, b = 2) {
      console.log(a + b)
    }
    fn()
    fn(5, 6)

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